1. Field of the Invention
The present invention relates to a semiconductor device and a manufacturing method thereof. Specifically, it relates to a semiconductor device including a wiring layer which contains copper as a main component and a manufacturing method thereof.
2. Description of the Related Art
From the demands of high integration of semiconductor devices in recent years, copper with a low resistance has come to be used as a material for wirings, plugs, and pads, etc.
It is described in JP-A-2005-158930 that a copper alloy film where an impurity is added to a copper film is adopted as a material for wiring as measures against the deterioration of reliability in the case of using copper. The aforementioned patent document describes a semiconductor device having a configuration in which the concentration of the impurity contained in at least one wiring layer of plural wiring layers increases with the width of the wiring.
JP-A-Hei6-177128 describes a semiconductor device which has a copper alloy thin film wiring containing aluminum or silicon. Moreover, JP-A-2004-039916 describes a semiconductor device in which a region containing unevenly distributed metal elements which are different from copper is provided at the vicinity of the upper surface of the metallic region containing copper as a main component.
JP-A-2006-253729 describes a technology for depositing a conduction film where a conduction material containing copper to which platinum etc. is added is deposited by a sputtering method and a buried wiring is formed by plating.